The present invention relates in general to a control system for an objective of a camera, in particular a film camera, and in particular to a control system of a type including one or several drive units for automatically adjusting the positions of at least one lens ring, e.g., for focus position, iris diaphragm and focal length. The drive units can adjust the lens rings or rings to a predetermined set position.
Conventional control systems of this type allow remote adjustment of various lens rings of a camera objective. The angular position of the respective lens ring which is preset in an adjusting device, is adjusted by a motor drive that always moves the lens ring from a current position to the next desired position in incremental steps. With this method, however, after several adjustment steps a cumulative error is introduced which can cause a noticeable misalignment. This misalignment interferes with the camera operation and may require a manual fine adjustment in regular intervals.
A larger number of tiltable film cameras that operate completely automatically and are able to attain specific camera positions, are already in use. These cameras are frequently located in areas that cannot be reached by a camera assistant. Movie scenes must then frequently be re-taken because the automatic adjustment of the lens rings is not accurate enough. The film takes then become unusable because the exposure is wrong or the scenes are not in focus.